#define _CRT_SECURE_NO_WARNINGS 1

#include "Snake.h"

void SetPos(int x, int y)
{
	// 获得设备句柄
	HANDLE handle = GetStdHandle(STD_OUTPUT_HANDLE);

	// 根据句柄设置光标的位置
	COORD pos = { x, y };
	SetConsoleCursorPosition(handle, pos);
}

void WelcomeToGame()
{
	// 欢迎信息
	SetPos(38, 10);
	printf("欢迎来到贪吃蛇小游戏\n");
	 
	SetPos(36, 20);
	system("pause");

	// 清理屏幕
	system("cls"); 

	// 打印功能介绍信息
	SetPos(18, 10);
	printf("用 ↑ . ↓ . ← . → 来控制蛇的移动，F3是加速，F4是减速");
	SetPos(18, 11);
	printf("加速能得到更高的分数");

	SetPos(18, 18);
	system("pause");
	system("cls");

}

void CreateMap()
{
	// 上
	SetPos(0, 0);
	for (int i = 0; i < 58; i += 2) {
		wprintf(L"%lc", WALL);
	}

	// 下
	SetPos(0, 26);
	for (int i = 0; i < 58; i += 2) {
		wprintf(L"%lc", WALL);
	}

	// 左
	for (int i = 1; i < 26; i++) {
		SetPos(0, i);
		wprintf(L"%lc", WALL);
	}

	// 右
	for (int i = 1; i < 26; i++) {
		SetPos(56, i);
		wprintf(L"%lc", WALL);
	}

}

void InitSnake(pSnake ps)
{
	pSnakeNode cur = NULL;
	// 创建五个蛇身的结点
	for (int i = 0; i < 5; i++) {
		cur = (pSnakeNode)malloc(sizeof(SnakeNode));
		if (cur == NULL) {
			perror("InitSnake():malloc()");
			return;
		}
		cur->x = POS_X + 2 * i;
		cur->y = POS_Y;
		cur->next = NULL;

		// 头插
		if (ps->pSnake == NULL)
		{
			ps->pSnake = cur;
		}
		else {
			cur->next = ps->pSnake;
			ps->pSnake = cur;
		}
	}

	// 打印蛇身
	cur = ps->pSnake;
	while (cur != NULL)
	{
		SetPos(cur->x, cur->y);
		wprintf(L"%lc", BODY);
		cur = cur->next;
	}

	// 贪吃蛇的其他信息初始化
	ps->dir = RIGHT;
	ps->FoodWeight = 10;
	ps->Score = 0;
	ps->SleepTime = 200;
	ps->status = OK;
	
}

void CreateFood(pSnake ps)
{
	// 食物是随机出现的，坐标就是随机的
	// 坐标必须在墙内
	// 坐标不能在蛇的身体上
	// x:2~54 y:1~25

	int x = 0;
	int y = 0;

again:
	do {
		x = rand() % 53 + 2;
		y = rand() % 24 + 1;
	} while (x % 2 != 0);

	// 坐标和蛇的身体的每个节点的做坐标比较
	pSnakeNode cur = ps->pSnake;
	while (cur != NULL)
	{
		if (x == cur->x && y == cur->y) {
			goto again;
		}
		cur = cur->next;
	}

	// 根据坐标创建食物
	pSnakeNode pFood = (pSnakeNode)malloc(sizeof(SnakeNode));
	if (pFood == NULL)
	{
		perror("CreateFood():malloc()");
		return;
	}
	pFood->x = x;
	pFood->y = y;

	ps->pFood = pFood;
	SetPos(x, y);
	wprintf(L"%lc", FOOD);
}

void GameStart(pSnake ps)
{
	// 设置控制台的信息（窗口大小、窗口名）
	system("mode con cols=100 lines=30");
	system("title 贪吃蛇");

	// 隐藏光标
	HANDLE handle = GetStdHandle(STD_OUTPUT_HANDLE);
	CONSOLE_CURSOR_INFO CursorInfo;
	GetConsoleCursorInfo(handle, &CursorInfo); // 获取控制台光标信息
	CursorInfo.bVisible = false;
	SetConsoleCursorInfo(handle, &CursorInfo);

	// 打印欢迎信息
	WelcomeToGame();

	// 绘制地图
	CreateMap();

	// 初始化蛇
	InitSnake(ps);

	// 创建食物
	CreateFood(ps);
}

void PrintHelpInfo()
{
	SetPos(60, 15);
	printf("1.不能穿墙，不能咬到自己");
	SetPos(60, 16);
	printf("2.用 ↑ . ↓ . ← . → 来控制蛇的移动");
	SetPos(60, 17);
	printf("3.F3是加速，F4是减速");

	SetPos(60, 20);
	printf("Author:tan90°=？");
}

void pause()
{
	while (1)
	{
		Sleep(100);
		if (KEY_PRESS(VK_SPACE)) {
			break;
		}
	}
}

int NextIsFood(pSnake ps, pSnakeNode pNext)
{
	if (ps->pFood->x == pNext->x && ps->pFood->y == pNext->y) {
		return 1;
	}
	else return 0;
}

void EatFood(pSnake ps, pSnakeNode pNext)
{
	pNext->next = ps->pSnake;
	ps->pSnake = pNext;

	pSnakeNode cur = ps->pSnake;
	// 打印蛇身
	while (cur != NULL)
	{
		SetPos(cur->x, cur->y);
		wprintf(L"%lc", BODY);
		cur = cur->next;
	}

	ps->Score += ps->FoodWeight;
	// 释放旧的食物
	free(ps->pFood);
	// 新建食物
	CreateFood(ps);
}

void NotEatFood(pSnake ps, pSnakeNode pNext)
{
	// 头插
	pNext->next = ps->pSnake;
	ps->pSnake = pNext;

	// 释放尾节点
	pSnakeNode cur = ps->pSnake;
	while (cur->next->next != NULL) {
		SetPos(cur->x, cur->y);
		wprintf(L"%lc", BODY);
		cur = cur->next;
	}
	// 将尾节点的位置打印成空白字符
	SetPos(cur->next->x, cur->next->y);
	printf("  ");

	free(cur->next);
	cur->next = NULL;
}

// 检测是否撞墙
void KillByWall(pSnake ps)
{
	if (ps->pSnake->x == 0 ||
		ps->pSnake->x == 56 ||
		ps->pSnake->y == 0 ||
		ps->pSnake->y == 26
		)
	{
		ps->status = KILL_BY_WALL;
	}
}

// 检测是否撞自己
void KillBySelf(pSnake ps)
{
	pSnakeNode cur = ps->pSnake->next; // 从第二个节点开始
	while (cur != NULL)
	{
		if (cur->x == ps->pSnake->x && cur->y == ps->pSnake->y) {
			ps->status = KILL_BY_SELF;
			return;
		}
		cur = cur->next;
	}
}

void SnakeMove(pSnake ps)
{
	pSnakeNode pNext = (pSnakeNode)malloc(sizeof(SnakeNode));
	if (pNext == NULL) {
		perror("SnakeMove():malloc()");
		return;
	}
	pNext->next = NULL;
	switch (ps->dir)
	{
	case UP:
		pNext->x = ps->pSnake->x;
		pNext->y = ps->pSnake->y - 1;
		break;
	case DOWN:
		pNext->x = ps->pSnake->x;
		pNext->y = ps->pSnake->y + 1;
		break;
	case LEFT:
		pNext->x = ps->pSnake->x - 2;
		pNext->y = ps->pSnake->y;
		break;
	case RIGHT:
		pNext->x = ps->pSnake->x + 2;
		pNext->y = ps->pSnake->y;
		break;
	}

	// 下一个坐标是不是食物
	if (NextIsFood(ps, pNext)) {
		// 是食物就吃掉
		EatFood(ps, pNext);
	}
	else {
		// 不是食物就正常走一步
		NotEatFood(ps, pNext);
	}

	// 检测撞墙
	KillByWall(ps);


	// 检测撞到自己
	KillBySelf(ps);

}

void GameRun(pSnake ps)
{
	// 打印帮助信息
	PrintHelpInfo();
	
	// 检测按键
	do {
		// 当前的分数情况
		SetPos(60, 10);
		printf("总分:%5d\n", ps->Score);
		SetPos(60, 11);
		printf("食物的分值:%2d\n", ps->FoodWeight);

		// 检测按键
		// 上、下、左、右、ESC、空格、F3、F4
		if (KEY_PRESS(VK_UP) && ps->dir != DOWN) {
			ps->dir = UP;
		}
		else if (KEY_PRESS(VK_DOWN) && ps->dir != UP) {
			ps->dir = DOWN;
		}
		else if (KEY_PRESS(VK_LEFT) && ps->dir != RIGHT) {
			ps->dir = LEFT;
		}
		else if (KEY_PRESS(VK_RIGHT) && ps->dir != LEFT) {
			ps->dir = RIGHT;
		}
		else if (KEY_PRESS(VK_ESCAPE)) {
			ps->status = ESC;
			break;
		}
		else if (KEY_PRESS(VK_SPACE)) {
			// 游戏暂停
			pause(); // 暂停和恢复暂停
		}
		else if (KEY_PRESS(VK_F3)) {
			if (ps->SleepTime >= 80) {
				ps->SleepTime -= 20;
				ps->FoodWeight += 2;
			}
		}
		else if (KEY_PRESS(VK_F4)) {
			if (ps->FoodWeight >= 4) {
				ps->SleepTime += 20;
				ps->FoodWeight -= 2;
			}
		}

		// 睡眠一下
		Sleep(ps->SleepTime);

		// 走一步
		SnakeMove(ps);

	} while (ps->status == OK);
}

void GameEnd(pSnake ps)
{
	SetPos(15, 12);
	switch (ps->status)
	{
	case ESC:
		printf("主动退出游戏，正常退出\n");
		break;
	case KILL_BY_WALL:
		printf("很遗憾，你撞墙了，游戏结束\n");
		break;
	case KILL_BY_SELF:
		printf("很遗憾，咬到自己了，游戏结束\n");
		break;
	}

	// 释放贪吃蛇的链表资源
	pSnakeNode cur = ps->pSnake;
	pSnakeNode del = NULL;

	while (cur != NULL)
	{
		del = cur;
		cur = cur->next;

		free(del);
	}

	free(ps->pFood);
	ps->pSnake = NULL;
}